Parent Company Information - Statements Of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net income	$ 30,741	$ 37,517	$ 32,888
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Gain on sale of securities, net	0	(67)	(98)
Unrealized loss (gain) on marketable equity securities	1,119	101	(61)
Stock-based compensation	742	1,073	943
Net Cash Provided (Used) by Operating Activities	78,123	111,989	(36,454)
Investing Activities:
Purchases of marketable equity securities	(3,934)	(493)	(1,552)
Proceeds from sales/calls/maturities of marketable equity securities	488	1,084	601
Net Cash (Used) Provided by Investing Activities	(405,625)	(159,089)	(382,825)
Financing Activities:
Dividends paid to shareholders	(10,571)	(9,388)	(8,844)
Proceeds from the issuance of common stock	586	1,543	84
Repurchase of common stock	(14,157)	(11,534)	(9,976)
Net Cash (Used) Provided by Financing Activities	(58,975)	576,962	439,820
Net Change in Cash and Cash Equivalents	(386,477)	529,862	20,541
Cash and Cash Equivalents at Beginning of Year	645,827	115,965	95,424
Cash and Cash Equivalents at End of Year	259,350	645,827	115,965
Northrim Bancorp, Inc.
Operating Activities:
Net income	30,741	37,517	32,888
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Gain on sale of securities, net	0	(67)	(98)
Equity in undistributed earnings from subsidiaries	(32,732)	(38,691)	(33,744)
Unrealized loss (gain) on marketable equity securities	1,119	101	(61)
Stock-based compensation	742	1,073	943
Changes in other assets and liabilities	(1,268)	(2,167)	(2,118)
Net Cash Provided (Used) by Operating Activities	(1,398)	(2,234)	(2,190)
Investing Activities:
Purchases of marketable equity securities	(3,934)	(493)	(1,552)
Proceeds from sales/calls/maturities of marketable equity securities	488	1,016	503
Investment in Northrim Bank, NISC & NST2	24,323	31,894	21,423
Net Cash (Used) Provided by Investing Activities	20,877	32,417	20,374
Financing Activities:
Dividends paid to shareholders	(10,571)	(9,388)	(8,844)
Proceeds from the issuance of common stock	586	1,543	84
Repurchase of common stock	(14,157)	(11,534)	(9,976)
Net Cash (Used) Provided by Financing Activities	(24,142)	(19,379)	(18,736)
Net Change in Cash and Cash Equivalents	(4,663)	10,804	(552)
Cash and Cash Equivalents at Beginning of Year	35,546	24,742	25,294
Cash and Cash Equivalents at End of Year	$ 30,883	$ 35,546	$ 24,742